When speaking with others, try to sincerely compliment them. This can help to make them feel better, build their confidence, and, hopefully, pay it forward to someone else. The opposite is also true if you improperly criticize them (even just nitpicking little things). That person will either be stripped of their confidence and be afraid to make any decisions, resent you and not want to be near you, or let it negatively affect their mood, which can rub off on others.
Be wise with when you praise others (sincerely, and mixing in private praise with public acknowledgement) and when to give them necessary constructive criticism (privately, relating it to how you may have done something similar in the past, and what you’ve learned from it).